<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script src="https://cdn.staticfile.org/vue/2.4.2/vue.min.js"></script>
	</head>
	<body>
		<div id="app">
		<input type="checkbox" v-model="a" />
		<label>{{a}}</label>
		<input type="checkbox" v-model="b" value="11" />
		<input type="checkbox" v-model="b" value="22" />
		<input type="checkbox" v-model="b" value="33" />
		<label>{{b}}</label>
		</div>
	</body>
	<script type="text/javascript">
		vm = new Vue({
		 	el:'#app',
		 	data:{
		 		a:true,
		 		b:[]
		 	},
		 	watch:{
		 		a:function(val){
		 			if(val==false){
		 				alert('111')
		 			};
		 			
		 		},
		 	}
		
		 })
		
	</script>
</html>
